Heather Mack, who is pregnant, and Tommy Schaefer could face the death penalty if found guilty of the premeditated murder of Sheila von Wiese Mack, 62, whose body was found in the case in the boot of a taxi in August.
Prosecutors alleged that Schaefer, who wept as he entered court, "blindly hit" Von Wiese Mack with a bowl in a fit of rage after she directed a racial slur at him during an argument. Schaefer is black.
"The defendant, overwhelmed with emotion and anger, picked up the glass fruit bowl and swung it at her face," prosecutor Eddy Arta Wijaya told the district court in the Balinese capital Denpasar, as he read out the 21-year-old's indictment.
"Wiese tried to push the handle towards Schaefer and it hit his mouth, making him angrier and more emotional. Using both hands, Schaefer blindly hit her as hard as he could between her eyes and nose with the fruit bowl."
He then continued hitting her face on the bed "until she stopped moving", he added.
Heather sits inside a holding cell at a court in Denpasar on Indonesia's resort island of Bali on Jan 14, 2015. - AFP Photo/Sonny Tumbelaka
The indictment said that 19-year-old Heather Mack hid in the bathroom during the attack before the couple stuffed the victim's body in a suitcase.
Mack and Schaefer, who went on trial separately, refused to speak to reporters after the trial. The next hearing will be on January 21.
The victim and the suspects are all from the Chicago area.
